Abbas *knows* that the Americans will feel obligated to veto this. What Abbas is relying on is that the Americans don't **want** to be put in that position i.e. Abbas is *relying* on the USA being desperate to stop that resolution ever getting to the floor of the UNSC. The price is well known: "the United States to articulate its support for the establishment of a Palestinian state within the 1967 borders". He wants THAT STATEMENT, and the threat of taking this to the UNSC is his way of getting it.
Egypt to hold parliamentary election in 2 phases starting Oct 18-19 (Reuters)
from the article: Abbas may turn to Washington or UN to support state recognition